I've big problem with checkbox fields. When i check the editable checkbox filed on the alv list is triggered "data_changed" and my handle method for this can change value ( set 'X' or space) by "modify_cell" method of "cl_alv_changed_data_protocol". But on the alv list on the screen i have still the same value as i was when i checked(not the value changed by my methods). The other fileds (dates, numbers etc) work correct. What's I've to do to resolve this problem. Any idea???